Gastonia Species Comparison

Arguably, life restorations of ankylosaurs (including nodosaur, polacanthines, etc.) are amongst the most challenging of all dinosaurs. A lack of good reference materials, the incomplete and eroded condition of many specimens, and a tendency to generalize on placement and shape of armor all contribute to incomplete and erroneous reconstructions (no criticism to artists out there - it's just really tough to find good references). 

Over the last couple of months I've been working on a project with Christa Sadler and Jim Kirkland to create reconstructions of the various environments across the stratigraphic range of the Cedar Mountain formation. As part of that work, Jim has provided me with invaluable reference materials and guidance on the reconstruction of the two Gastonia species: G. burgei (from the Upper Yellow Cat member) and G. lorriemcwhinneyae (from the Poison Strip member). Much of Jim's work on this was featured in his talk at DinoFest in January. 

Many of the elements shown in these reconstructions have not (to the best of my knowledge) been reflected in previous reconstructions, including the row of low, rectangular osteoderms just anterior to the shield and surrounded by small, rectangular and oval ossicles; the large, rectangular hip plates, the scale-covered "crab" or "spider" formation at back of the skull, and the arrangement of lower paired plates stretching from the neck all the way along the back to the shield. Also of note is the large "splate" aligned with the 3rd cervical ring on G. lorriemcwhinneyae, as well as the other two large lateral neck spikes.

There's some disagreement about the number of cervical rings. Gastonia has typically been depicted with two, but Jim believes there were three. 

G. lorriemcwhinneyae appears a bit later than G. burgei in the fossil records, and Jim believes the pointier, more elaborately shaped armor may reflect an evolutionary adaption to the large dromaeosaurs that were evolving during that time.